1. Field of the Invention
The present invention relates to a process for decomposing vulcanized rubber.
2. Description of the Prior Art
As the result of recent remarkable development of motorization, the amount of used tires has increased rapidly and its treatment has become a big problem. Heretofore, used tires have been used for filling-up, the structural shape itself has been used or they have been simply burned. However, these treatments are not desired from viewpoint of prevention of environmental pollution and effective use of material resources.
For the purpose of fulfilling the above-mentioned demands, reclamation of used tires has been carried out since a long time ago. Studies on reclaiming used vulcanized rubber have recently become active, and various new processes and agents for reclaiming have been proposed in succession.
A thermal decomposition process which is recently noted is one of treatments for used tires. In this process, used tires are thermally decomposed at high temperature between 400.degree. C. and 900.degree. C. by a dry distillation method which is carried out under anaerobic conditions on a partial combustion method to yield gas, oil and solid residues. The resulting gas and oil are used for fuel and the resulting solid residue is used for carbon material.
There has been recently proposed a process in which vulcanized rubber is mixed with oils and decomposed at lower temperature than that of the above-mentioned process, namely, at 210.degree.-400.degree. C. in an autoclave or screw extruder to produce a molten product of vulcanized rubber. However, these processes require higher temperature than 200.degree. C. to decompose vulcanized rubber. Therefore, it is desirable that a reclaiming process which is carried out at lower temperature, with less consumption of energy at a reduced cost is developed.
Although a few papers have been reported on reactions of peroxides with unvulcanized rubber and decomposition of unvulcanized rubber with peroxides, there have not been any reports on decomposition of vulcanized rubber with peroxides.